1. Field of the Invention
The present invention relates to systems and methods for analyzing a fresh commodity, and, more particularly, to such systems and methods for identifying the geographic origin thereof.
2. Description of Related Art
Fresh produce is often labeled with its geographical origin when that origin is believed to confer a beneficial attribute. Such indicators include “Vidalia onions,” “Idaho potatoes,” and “Florida citrus.” Federal and state laws have been enacted to ban mislabeling of fresh produce, and cases of alleged misrepresentation have been investigated by the U.S. Department of Agriculture, state governments, and grower groups.
One detection method involves the analysis of vitamins or other organic molecules. Such compounds are, however, subject to variability owing to degradation over time and to storage conditions.
Another way that has been used is to test for the concentration of certain elements in a product, which can be affected by such things as the soil in which the product is grown. The soil-plant system is highly specific for different elements, plant species, and environmental conditions. Under most conditions, a trace element present in the commodity must have existed in the rooting zone of the plant, generally in highly soluble form. A trace element must also pass through at least one cellular membrane in its movement from soil to plant. The selectivity of these processes of mineral accumulation within the commodity varies with different trace elements, with different plants, and the unique environment in which the commodity is grown.
An example of geographic origin variability is the higher barium levels typically found in Brazilian than in Florida oranges, which can thus be used as an indicator of adulteration. The use of trace metals to define geographical origin of orange juice has been described using inductively coupled plasma-atomic emission spectrometry (ICP-AES) data subjected to a multivariate pattern recognition algorithm and artificial neural networks (Nikdel et al., in Nagy et al., Adulteration of Fruit Juice Beverages, Marcel Dekker, New York, 1988; Nikdel, in Nagy et al., Methods to Detect Adulteration of Fruit Juice Beverages, Vol. I, Agscience, Inc., Auburndale, Fla., 1995).